1, car paint. Mainly depends on whether the car paint and side seams are in good condition. If the color difference of the car paint changes greatly, it may be because of the collision and the car has been repaired. When checking the car body, you can measure it with a paint film meter. Detecting the thickness of paint is an important means to detect whether there is an accident in the automobile. In general, it is normal for the paint thickness to exceed 100 micron, 200 micron is spray painting, and more than 300 micron is sheet metal.

2. Other appearances. In addition to the car paint, there is also whether the car body is deformed. If the flatness of the original iron sheet of the car body is trimmed smoothly, you can see the difference. It also depends on whether there is repair welding on the body or frame to avoid buying accident cars or overhauled used cars. For example, whether the gap at the joint of the car body is flat and consistent, whether the screws at key parts are passive, whether the door switch is smooth and silent, whether the carpet under the trunk has burnt marks, and so on.

3. Engine. The engine of a car directly determines the quality of the car. When observing, you can check whether there is oil leakage inside the engine. The key point is whether there is abnormal noise in the engine and whether the gearbox shifts gears.

4 trunk. Pay attention to whether there are sheet metal marks on the back of the trunk, such as whether the transition is not smooth enough and whether there are obvious impact repair marks. If there is a spare tire, it is necessary to check whether there is sediment under the spare tire to judge whether there is a soaking car in the vehicle.

5. Inside the vehicle. Generally, the service life of a vehicle can be inferred by checking the internal wear of the vehicle. The seat belt, seat bottom, cab floor and seat belt must be carefully observed for dirt and water stains. In addition, the electronic components in the car, such as lighting, audio, central control panel, electric seat, air conditioner, electric sunroof, etc., also need attention.

6. Operation structure. The tread depth of automobile tires should be at least 4 mm; The four tires and spare tire should have the same brand, size and structure. The degree of tire wear should be uniform, and the center point of the wheels on both sides, that is, the wheelbase size, should be consistent; Whether there is oil stain on the shock absorber indicates whether the shock absorber is excessively worn and poorly sealed.

7. Check the driver's license. Check whether the engine, car body and other identification numbers are consistent with the documents, whether all kinds of documents are complete and effective, and whether the original owner's "four certificates and one photo" are complete and true. "Four certificates and one photo" can check whether the following contents are consistent: registration date, annual inspection time, owner, model, etc. Let's look at other relevant procedures, such as the owner's ID card, the unit passenger car's quota certificate or use certificate, the operation certificate, the unit certificate, the business license, the official seal, the judicial ruling, and the truck auction certificate. Finally, see if the vehicle model, color, license plate number, frame number and engine number are consistent with the four certificates. If there is no doubt, you can trade.

Step 2: "Ask"

You can quickly know the basic information of the car by asking. Before buying a car, it is best to find professionals and relevant staff of 4S shops to check the actual built-in mileage, vehicle insurance policy, purchase time maintenance record, vehicle registration date, annual inspection time, etc. Through special computer equipment, we can know the basic situation of the vehicle.

Step 3: "Try"

The so-called "test" is to personally feel the performance of the car on the road. When testing on the road, you need to pay attention to whether the start is smooth, whether the acceleration is smooth, whether the steering is stuck, whether the braking is sideslip and tail-flick, whether the driving is smooth, whether the ride is comfortable, whether the steering wheel is deviated, whether the chassis is abnormal, whether the interior parts are abnormal, whether the engine is running normally, and whether the gearbox is abnormal.

Finally, if you don't know much about cars, don't think that you can test used cars by learning temporarily on the Internet. Detecting used cars is a complicated job, which is not as simple as what you see on the Internet. Moreover, you need to look at sophisticated experience when you encounter fine car repair. It is recommended to find a third-party testing agency similar to Dr. Cha.